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[ICEM] Aligning Edges?

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Old   October 29, 2012, 09:45
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Dear All,

I work a lot with pipeflows and have a perseverative problem.
My blocking generally looks more or less like the attached picture.
picture.jpg
In the curved regions, I need to insert these additional splits (blue arrow). Otherwise I get negative volumes, cripples cells etc.
Now, when I "spline split" the edges to get them closer to the actual pipe in the bends (orange arrow), I can not align these points to the surface. All I do is "by hand", which is not really precise to my taste (especially in 3d).
Is there any better way to align edges to a pipe? Also the inner edges of the O-grid cause the same trouble.

Thanks in advance.
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Old   October 29, 2012, 10:21
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No need to split edges. Just extrude faces along curve and insert two or three additional splits.

If you use these split edge function, you've to adjust the interior edges by "link edge".

usually, icem projects edges to nearest surface (if not associated in another way). if you use this split edge function (linear or spline), the mesh will follow exactely this shape instead of projecting to nearest surface. It's always better to associate edges to geometry (or any other association), as this split edge function is a more "tricky" thing, for example to improve cell angles in a very complex topology
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Old   October 29, 2012, 10:27
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Hi! Thank you for your reply.
What do you mean by:
Quote:
Originally Posted by energy382 View Post
Just extrude faces along curve
?
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Old   October 29, 2012, 10:42
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blocking/create block/extrude faces/along curve

Just select faces from your o-block and extrude them along your curved line (repesenting the curved part of your pipe surface).

If you provide .tin-file, I can clarify my thoughts
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Old   October 29, 2012, 12:56
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i have dealt recently with curved tubes, if you go with extrude along curve, do it step by step, otherwise you will get negative volumes cells. remove all associations for the curves, then associate only the one that they seem difficult for icem to associate, (don't know if was clear).
Suddenly i have an idea i wanna try, please if you can share the tin...
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Old   October 29, 2012, 13:05
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Hits from Ansys official presentation :

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Old   October 30, 2012, 06:04
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Quote:
Originally Posted by energy382 View Post
blocking/create block/extrude faces/along curve

Just select faces from your o-block and extrude them along your curved line (repesenting the curved part of your pipe surface).

If you provide .tin-file, I can clarify my thoughts
I create the geometry file using DesignModeler and use the "Workbench Readers" to import the geometry to ICEM. Right now the only curves are inlet and outlet "circles" and a few intermediate circles. I never used the "extrude faces" command, but is it correct that I need to create a curve (maybe in DM) along the pipe and than use it as the "Extrude Curve" ? What is the best location for that curve, in the middle of the pipe or somewhere at the wall?

Edit:
It works. Thank you very much!
screen_2.jpg

Last edited by RodriguezFatz; October 30, 2012 at 07:35. Reason: I got it!
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Old   October 30, 2012, 08:27
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Next Problem: When I continue the extrusion, (starting with the picture above) I get the error message "Extrusion of faces failed".
Any ideas?
test_pipe.zip
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Old   October 30, 2012, 09:41
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Wow. It is failing at point of inflation
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Old   October 30, 2012, 10:01
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done. Needs following steps

1. Use extrude along curve first until it fails.

2. If needed merge some curves and avoid this process when curve is changing its direction (needs confirmation from Simon)

3. If along curve extrusion fails then use fixed distance for very small distance and then continue using the extrude along curve. This block can deleted and vertices can be merged to maintain the connectivity.

4. Number of layers 5 to 10

5. O-grid should be created in last.

This is working for me on your geometry. See this image :







Attached Files
File Type: zip test_pipe.zip (49.2 KB, 5 views)
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Last edited by Far; October 30, 2012 at 12:34.
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Old   October 30, 2012, 12:34
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icem handles the extrusion better in the unstructured level... tried it yesterday on a 90 curved tube and it worked
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Old   October 30, 2012, 14:31
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Thank you Far, you are the best!
Just for the future: How can I create a geometry, that can be swept without this workaround? I mean, this pipe seems to be pretty simple, what's the problem here?
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Old   October 30, 2012, 14:39
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Problem is that blocks are straight with rectangle shape and ur task is to get of shape of the underlying geometry. ICEM has automatic capability to project the faces to the nearest surface but that should be within some limits.
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